In order to create more complex and dynamic web applications, PHP offers a huge list of predefined variables. These variables not only simplify your task but also saves you from writing thousands and thousands lines of codes. These predefined variables in PHP ensure the security of applications from external threats. Using these variables you will be able to upload and download files dynamically. You can also generate several request to your server.
Though there are a huge list of predefined variables in PHP, we will talk about most commonly used variables. See the list below.
List of most commonly used predefined variables in PHP
$_GET and $_POST are most commonly used variables in PHP, which is required to get data from users. $_GET and $_POST are associative array of variables that is passed to the current script via the URL parameters HTTP. Where as $_FILES is an associative array of items uploaded to the current script using HTTP POST method.